Portable electronic instruments such as oscilloscopes are often required to be portable for testing devices at various locations. Accordingly, they are typically provided with carrying handles. A typical configuration of portable oscilloscope has a rectangular front interface panel with a width substantially greater than its height. To accommodate a lengthy cathode ray tube (CRT), the instrument has an even greater depth than its width. The handle is typically a bail handle pivotally mounted to opposite side panels at positions near the front panel. The handle has arms that extend parallel to the side panels, with a cross member connecting the handle ends.
The handle may be moved among several positions, and has locking mechanisms at each pivot mount to secure the handle in any of several possible positions. When transporting the instrument, the handle is positioned with its arms extending perpendicular to the front panel, and the handle cross portion bisecting the front panel. Thus, the instrument may be carried as a suitcase, with the rear panel facing downward, and the center of the instrument in line with and below the handle for stability. With the pivot mounts being positioned nearer to the front panel than to the side panel, the instrument is stable without torsional stress applied to the pivot mounts.
The handle of the described conventional instrument may be positioned below the plane of the bottom panel to elevate the front panel and angle it somewhat upward from a vertical position. While the rear edge of the instrument rests on a bench surface, the front edge elevation and angle may be selected based on the angle of the handle below the plane of the instrument housing. When the instrument is to sit flat on a horizontal surface, the handle may be stowed by pivoting it to a position above the instrument, folded back until it contacts a rear portion of the upper surface of the instrument housing. The handle may also be removed for rack mounting. The limited arm length of the handle is adequate to provide knuckle clearance during carrying without being undesirably bulky or providing an excessively long lever arm to stress the locked pivot mounts.
In conventional instruments as described, the mass and lengthy front-to-rear "wheelbase" provides substantial stability even when buttons on the front panel are pressed with significant force by a user. However, current oscilloscope designs are much more compact and lightweight than traditional designs. In addition to miniaturization of many electronic components, the substitution of flat panel displays for bulky and heavy CRTs has radically changed product configurations. A typical current device may have a front panel with proportions similar to the conventional instrument described above, but with a much smaller housing depth. Whereas the depth was formerly typically the longest dimension, it may now be the smallest, as front panel area becomes a size-limiting constraint instead of the traditional volume or CRT length constraints. Further, the elimination of a fragile and heavy CRT has allowed the use of lighter housing and structural materials, drastically reducing the mass of such instruments, which formerly provided bench-top stability during use.
With lighter instruments and shallow housing depths comes a stability disadvantage. A user pressing a button or inserting a probe connector near the upper edge of an instrument's front panel may tend to tip the unit backwards. In addition, the use of a prop at the lower edge of the front panel to provide front elevation and a sometimes-preferred viewing angle for a user above the level of the instrument worsens the stability concern. Such props elevate the center of mass of the instrument, and shift it slightly rearward with respect to the lower rear edge of the housing, which serves as a fulcrum for stability purposes. Even when tipping is not a concern, existing compact instruments lack desired viewing angle versatility. Accordingly, there is a need for a compact instrument that can be positioned for a variety of useful viewing angles, and which is stable to resist tipping during use.
The embodiments disclosed herein overcome these limitations by providing an electronic instrument with a housing having a front surface and a rear surface. A user interface is located on the front surface. A movable handle having a grip portion is connected to the housing and is movable between a first carrying position in which at least a portion of the grip is forward of the rear surface and a first stabilizing position in which at least a portion of the grip is rearward of the rear surface. The handle may movable to other stabilizing positions, and the housing may include a front prop to provide additional stability and alternative viewing angles.